Since its origins, the field of behavioural economics has explored many aspects of human beings’ decision-making. Among these, particular attention has always been given to entrepreneurs and their exposure to cognitive biases, meaning systemic errors in taking decisions. As reported in literature, these biases do have a negative impact on firms’ financial performance, especially when it comes to small businesses. This thesis’ objective is to expand the current knowledge about SMEs entrepreneurs’ rationality when making strategic decisions. Specifically, three cognitive biases have been discussed and investigated: overconfidence, the planning fallacy, and the status quo bias. The study developed around a questionnaire mainly based on Likert scale questions, assessing the presence and the intensity of such biases in the population of fruit growers in Piedmont, Italy, with a numeric score between 1 and 5.